Minimally invasive surgery (MIS) has allowed physicians to carry out many surgical procedures with less pain and disability than conventional, open surgery. Unlike conventional open surgery, where the surgical site is readily accessible through a large incision, enabling the surgeon to easily visualize and manipulate both tissue and instruments, MIS requires the surgeon to operate remotely by inserting and manipulating instruments through small punctures (“keyhole surgery”) or through natural orifices, including the vagina, the esophagus, or the anus.
In MIS, a small puncture is typically made in the body. Medical instruments are then inserted through a cannula. A cannula has a small inside diameter, typically 5-10 millimeters (mm), and sometimes up to 20 millimeters (mm) or more. A number of such cannulas are inserted into the body for any given operation. Minimally invasive surgical instruments are necessarily smaller, and are also generally longer and therefore are more difficult to manipulate with precision.
Perhaps the most problematic surgical task in MIS is suturing. Suturing requires coordinated manipulation with both hands of small needles and sutures that are difficult to visualize (particularly when only indirect, two-dimensional video imaging is available) as well as the several instruments (including needle-drivers and pick-up forceps) ordinarily used to suture by hand. In an environment characterized by limited space, limited visualization, and limited mobility, many surgeons find minimally invasive suturing by hand an extremely difficult, often virtually impossible, surgical task.
In the preferred method of suturing by hand, a grasping forceps (“needle driver”) is held by the surgeon and is used to grip a curved needle near the needle's tail. Pronation of the surgeon's wrist drives the needle into the tissue. When the point of the curved needle emerges from the tissue, the surgeon releases the needle from the grip of the needle driver and grasps the point with another forceps (“pick-ups”). The surgeon then pulls the curved needle by the needle point, preferably in a circular path following the arc of the needle's curvature to follow the most atraumatic path through the tissue, until the entire length of the needle has exited the tissue. Each time a stitch is placed, the curved needle is thus driven around in a complete circular arc. Individual (interrupted) stitches are placed by tying off the suture following the placement of each stitch. Running (continuous) stitches are placed by repeatedly driving the curved needle in a complete circular arc repeatedly until the desired length of suture and number of stitches has been placed. In order to place additional interrupted or continuous stitches, the surgeon must let go of the point of the needle and re-grasp the needle near the needle's tail.
In the manual suturing technique described above, the direct handling of the needle can result in accidental needle pricks through a surgeon or nurse's gloves, posing a potential risk of infection for the surgeon, nurse, staff, and patient, or cause the needle to become contaminated with pathogenic bacteria that can cause onset of infection at the site of the sutures. There is also a risk of the needle penetrating internal organs or vessels and causing a serious, and often fatal infection.
Various devices for suturing for MIS are described in U.S. Pat. No. 5,643,295 entitled “Methods and Apparatus for Suturing Tissue”; U.S. Pat. No. 5,665,096 entitled “Needle Driving Apparatus and Methods of Suturing Tissue”; U.S. Pat. No. 5,665,109 entitled “Methods and Apparatus for Suturing Tissue”; U.S. Pat. No. 5,759,188 entitled “Suturing Instrument with Rotatably Mounted Needle Driver and Catcher”; U.S. Pat. No. 5,860,992 entitled “Endoscopic Suturing Devices and Methods”; U.S. Pat. No. 5,954,733 entitled “Suturing Instrument with Rotatably Mounted Needle Driver and Catcher”; U.S. Pat. No. 6,719,763 entitled “Endoscopic Suturing Device”; and U.S. Pat. No. 6,755,843 entitled “Endoscopic Suturing Device”, all of which are incorporated by reference in their entireties for the teachings therein.
Assignees' U.S. Pat. Nos. 5,437,681,5,540,705 and 6,923,819 disclose a suturing device with thread management comprising a protective cartridge, suturing needle and needle rotation drive, the disclosures of which are hereby incorporated by reference. The devices described in the above-mentioned patents and patent application comprise a mechanism for driving a protected needle however, the needle is rotated about an axis that is parallel to the axis of the device. In addition, the orientation and size of the suturing device makes it difficult to visualize and cumbersome to use for MIS.
Therefore, there remains a need in the art for a minimally invasive suturing device that is easily manipulated within the small diameter of the cannula; functions in an environment characterized by limited space, limited visualization, and limited mobility; mimics the preferred method of suturing used by surgeons; permits the surgeon to secure and tie knots quickly and with controlled tension; places continuous stitches; and protects user's from accidental needle sticks during needle handling, as well as internal organs and vessels, from inadvertent needle-pricks.